Variable pitch propeller



Filed Dec. 10, 1948 5 Sheets-Sheet 1 Jan. 2, 1951 E. c. HATCHER 2,536,546

VARIABLE PITCH PROPELLER J 1951 E. c. HATCHER 2,536,545

VARIABLE PITCH PROPELLER Filed Dec. 10, 1948 5 Shets-Sheet 2 Jan. 2, 1951 E. c. HATCHER VARIABLE PITCH PROPELLER 5 Sheets-Swat 3 Filed Dec. 10, 1948 Jan. 2, 1951 c, HATCHER 2,536,546

VARIABLE PITCH PROPELLER Filed Dec. 10, 1948 5 Sheets-Sheet 4 Jan. 2, 1951 E. c. HATCHER VARIABLE PITCH PROPELLER 5 Sheets-Sheet 5 Filed. Dec. 10, 1948 Patented Jan. 2, 1951 vet 'leets zi taeea EI nest Charles Hatoher, Nort-hwood,

England,

assignor to 1. Stone!& Company-Limited, Dept;v {and England, aoorporation of Great Britain egg, a i n D909 rials invention mm s to improvements variable pitch propeller mechanism foe marine purposes and particularly fo-rsubmarine vessels. The principal object ofthe invention i's-to pro-v vide a simplified mechanism adapted for run. ningreliably ior long periods without attention and with no demandfor' oil lubrication.

The mechanism with which the invention is. concernedis of the kind wherein the propeller-- blades are revolubly adjustable about pintles' by means of rack rods meshing with toothed gears at the roots ei the 131101381161 blades the rack rods; havingtheirforwa-rd ends coupled with a. screw;- operated sleeve device for moving the rack rods to and fro in ordei to adjust the piteh of the 910-.

pellen blades. 7 i v f Heretof ore, the rack. rods were figgedly connected; at their-- for-ward; end to a flangeot the sleeve device, so that the said sleeve devise was-carried around with the propeller-- when revolving a thrust ooupling being provided between the {pi war-d end ofthe sleeve device and the operating sorew. 1

According to the present invention each rack- Tod'is provided with its own individual thnust oo'upling for engagement with-the sleeve devicewhich thereiore does not revolve with the pl epellet, whereby there is a degree of freedom {e1}- ach raol; rod and greater'ea'se and i eliabilityof; ionizing are achieved. Advantageously. one

'rnember-tof' the screwdevice is; an extension oi:

the stem tube on bracket bear-ingof" t e vesseland the othen member has a flange ton engaging I with the individual thrust couplings oi?- the meltr ocls; The thnust couplings preferably oomppise i ockable pads made. of a synthetic plastie ma; terial, the rack rods and revelublu adjustable blades of the. pr'c'anellerbeingalso provided with. hearing surf aces of this material'..- The syntheticpla'stio. material bear-ingaga nst-metal surfaces is-lubrieated' bythewater of' immetsion, with the result that the mechanism can be relied: upon to work" efficientlyforlong periods without requiring inspection and attention. With this improved. mechanism the propeller shaft requires. no 'modi ,fication or cutting. or drilling: operation when the.- mechanism is fitted. It is-thusnossible tofitthe mechanism to. existing vessels, the. only requires merit; being; to mount. one memben of the scyve device as extension otthe stem. tube. l e a com an ng gnawin e m les at me an sm n ccordaneelwith the nvent ee ar illu tr t d as. follows:

F u a is. n. s upn rha f a. e tralle itns din lse tion a d n. the ow a a the at the ewest sextet.

mm;- '10. 194 se ia 6.4.6 in Decem Figuge- 3-, whioh is a continuation of Fight-e 1-, shows-in its uppen half a central longitudinal see-l tionthrough "the propellerand in its lower hal f a section taken divefgently so as to disclose a view of one of the rack rods.

Figure 3 is a tran sverse sectionthrqugh the pintles of the propellerblades.

Figure eis; a transversesection taken on the lineIV-glfin Figure l.

Figure 5 is a detail section to a larger scale, illustrating the mounting of one of the thrust padsseen Figures 1 and 4 v Eig-u e E isa longitudinal section illustrating a modified arrangement enabling the operating mechanism to be disposed inboard, that is to say inwardly-oi the stern structure of a vessel, and

Figure 7-isa longitudinal section illustrating a furt er m fi on;

Referring to Figure l, a is the stern struetuigeofa vessel and b is the stern-tube through which passes the propeller: shaft 0. The fixedniember off the screw device which is operated for varying; the pitch of the propeller; blades is a" length of; tube ct which is passed over; the propeller shai t "q so that an en d flange d comesfagainst an end flange b at the stern tube b. The tube d'is Se:

ourecl by boltsv e which also pass through the flange bl and screw into a ljillg' f on the stei n structure a. The tube ct is formed externally a male screw thread and on to this tube d there is 'screwedan internallyscrew threaded nut sleeve o Qn the forward end of the nut sleeve 5] there" is a lai ge bevel wheel h which isprevented ii -om tul n-ing; in relation to thenut sleeve 9 by a key on feathei whioh neverthe ess permits the nut sleeve g. to moveaxiallyin relation to the bevel wheel hI Thi'swheellis made in halves, the two halves-beingput togethenarou-nd the. nut sleeve gandfastened to one. anethenbyv bolts h; lhewheel: h is formed" with. an annular extenti-on h having an intumed lip. 77. which engages. in a groove. for-med inthe periphery of: the. flange d Phis engagement pre vents the. wheel it from moving in the axial di-r section whilst leaving it free. to revolve. A bevelmerit; of this flange endwise of the sleeyegis prethree-.bl. dad n opel tented by a. te i in ring 1 The. flangelfotm s; art at a hrus eoup nebetw n the nu v s v 9? thr e. ods. m, see a so. F gure. 3, which.- se -ve rs eluh v d ustin th bl d i: a as Manatee-sealants.

a. M A... we

taken centrally Each rod m is separately coupled with the flange l in the following manner: The forward end of a rod m is reduced in diameter and screw threaded for screwing into a boss n projecting axially from one side of a segment n, and, as will be seen from Figure 4, each segment n extends around a little less than 120. As seen in Figure 1, the segments n are of L-section to provide a radial wall and a peripheral wall surrounding the flange I. On the radial wall of each segment there are three pivots serving for the mounting of three arcual thrust pads 19. These pads are made from a synthetic resin with a fibrous constituent and,

as seen in Figure 5, a small brass plate p is attached by screws to the back of each pad so. as to lie between the latter and the radial wall of the segment 11., the plate 12 being moreover to one side of the pivot pin 0. The forward or open end of each segment n is closed by an arcual plate q which is bolted to the segment and which provides a second radial wall opposed to that of the segment and serving for the mounting of a second set of thrust pads r in a manner similar to that above described for the pads p. The thrust of the nut sleeve g on the rack rods m is therefore transmitted in one direction by the pads p and in the opposite direction by the pads r. The pads p and 1' are free to turn slightly about the pivot pins 0 and are also free to tilt slightly out of their normal plane about the edges of their respective backing plates 12 and by'this means the pads are at all times able to adjust themselves to the best position for transmitting the thrust. Moreover, as each rack rod m has its own individual coupling with the flange Z, free working of the rods m at all times is assured. Each segment n is formed at a mid-point of'its periphery with a rib n and the ribs n fit slidjecting flange 2 which engages in a recess formed around the root of the blade, the underside of each flange 2 being fitted with a bearing ring .2 of synthetic resin material. The two halves of the retaining ring a are put together around the root of a blade 0. with the flange parts 2 engaged in the recess and the blade is then mounted upon its pintle v whereupon the retaining ring e'is fastened to the boss t of the propeller by the screws 2 seen in Figure 2. When the propeller is revolving, the blades i; tend to move outwards under centrifugal force but are restrained by the flanges 2 of the retaining rings 2. Thus, if the ably in respective slots s formed in the axial di- Referring to Figures 2 and3, it will be seen that v the rack rods m are slidable in bores formed in the boss 25 of the propeller, the bores being parallel with the axis of the propeller shaft 0. The rear end portion of each rod m is formed with rack teeth m on one side and on the opposite side each rod is formed withtwo grooves for the reception of bearing strips u made of the synthetic resin material already referred to.

In the case of a three-bladed propeller, the boss t is formed with three pintles t for the mounting of the propeller blades 1*. The pintles t and the corresponding recesses in the roots of the propeller blades, are somewhat conical but at the tip and root of each pintle there is a cylindrical formation these being surrounded by bearing liners'in the form of sleeves w and a: made of synthetic resin material. These sleeves provide bearings for the blades 1) to turn around when changing pitch.

To the root of each blade 1) there is attached by screws, as seen in Figure 2, a ring y and around a segment of this ring teeth y (Figure 3)' are formed for meshing with the teeth m of a rack rodm.

Referring again to Figures 2 and 3, it will be se'en'that around each pintle t the boss t is formed with a circular recess for the reception of the root of a blade 22 and a blade-retaining ring a. The latter which is divided diametrically intotwo halves is formed with an'inwardly problades 22 are turned around the pintles t to change the pitch whilst the propeller is revolving, the rings 2 provide good thrust bearings for the blades to turn against.

As will be seen in Figure 2, a hole 3 is formed in each blade 1; from the surface thereof to the top of the recess which fits over pintle t When the propeller revolves, the centrifugal action in duces an outward flow of water through the holes 3, whereby a flow of water for lubrication purposes is caused to take place over the bearings 2 x and w. Moreover, owing to the thickness of the bearing strips u on the rack rods 171. water can pass along these rods, as will be understood from Figure 3, for the lubrication of these sliding bearings.

1 The operation of pitch changing is performed as follows: The shaft is, Figure 1, is turned in one direction or the other and the pinion a imparts corresponding turning movement to the bevel gear wheel h which carries with it the nut sleeve g. The turning of the nut sleeve 9 causes the latter to screw itself, in one direction or the other, along the fixed and non-revoluble screw threaded tube (1. This axial movement of the nut sleeve g is imparted by the thrust flangel either to the thrust pads p or to the thrust pads r whereby the rack rods m are moved to the right hand or to the left hand in Figure 1. As will be clear from Figure 2, such movements of the rods m cause the blades 1; to turn around the pintles t through a desired angle, owing to the meshing of the teeth m of the rods with the teeth 1 on the rings y secured to the roots of the blades. When the propeller is revolving and the shaft 7c is at rest, the rods m and thrust coupling parts 12 are revolving in relation to the flange I which is not revolving. The force reacting on the blades and tending to turn them about-the pintles t is resisted by the thrust pads p or 1' bearing against the stationary flange 1. As water is freely admitted to the thrust-bearing, the pads 10 and 1' are constant y lubricated, so that they are in efficient working condition at all times and the resistance due to the pads rubbing against the flange lis easily overcome when the flange Z and nut sleeve 9 are turned by the gearing y'h fora pitch-changing operation.

- To prevent jamming, the nut sleeve g is fitted at each end with stop rings 4 and 5. When the sleeve g arrives at the limit of its movement in the rearward direction, the stop ring 4 comes against a stop ring 6 fixed at the rear end of the tubeid. When the sleeve g arrives at the limit of its- 'movement in the forward direction the stop ring 5 comes against a stop ring I mounted on the flange d at the forward end of the tube d. The mechanism seen in Figure 1 may be protected by enclosing it in a casing bolted to the stern strucure a, water being admitted to the interior of the casing through a suitable strainer.

It will be apparent that suitable changes'can between the sleeves I and II.

readily be made to suit propellers having a different number of blades.

According to the modification illustrated in Figure 6, the fixed member of the screw device is an internally screw threaded sleeve I0 extending inwardly of the vessel from the stern structure a. This sleeve It thus forms an inward extension of the stern tube b which is fixedly mounted in the stern structure a. The rear end of the sleeve I9 is formed with a flange IIl for bolting the sleeve III to the stern structure a and it is also formed with a screw threaded hole Ill for the mounting thereon of a lubricating device. 0n the propeller shaft 0 there is slidably mounted a long sleeve II which extends from within the vessel through the sleeve II] and through the stern tube b. At its inner end this sleeve has keyed to it a toothed wheel I2. Over an intermediate portion of its length, the sleeve II is formed with a male screw thread I3 for engaging with the internal screw thread of the sleeve I0. At its rear end, the sleeve II is fitted with a thrust flange Z similar to that described with reference to Figure 1. The internal diameter of the sleeve II is a little larger than the diameter of the propeller shaft 0 and is suitably recessed along portions of its length for the reception of liners I4 which ma be of synthetic resin material. These liners I4 provide bearing surfaces between the sleeve II and the shaft 0. A packing I5 is provided in the open end of the sleeve ID to prevent escape of lubricant On the inner end of the sleeve II there is screwed a stufling box IE containing a packing I! to prevent escape of lubricant between the sleeve II and the shaft 0. The toothed wheel I2 is in mesh with a pinion I8 and the width of the teeth of the pinion I8 is several times the width of the teeth of the wheel I2. The operation is as follows: In order to change the pitch of the propeller blades, the pinion I8 is turned to drive the toothed wheel I2 and the sleeve I I in one direction or the other. When the sleeve II is turned, the screw thread I3 thereon works in the internal screw thread of the sleeve I9 and thus causes the sleeve II to move axially in one direction or the other. Owing to the width of the teeth of the pinion I8, the toothed wheel I2 which is fixedly mounted on the sleeve H can move either to the left or to the right in Figure 6 whilst still remaining in mesh with the pinion I8. The axial movements of the sleeve II are transmitted to the pitch-changing mechanism by means of the thrust flange Z and the thrust coupling means described with reference to Figure l. The liners I4 provide bearing surfaces for the propeller shaft 0 when the latter is revolving and they also serve as sliding bearing surfaces when the sleeve II is adjusted axially along the shaft 0 for pitch changing. During this operation, the sleeve I I turns and slides axiall within the stern tube 19 as its bearing. In this modification, the control mechanism comprising the gears l2 and I8 is entirely within the vessel.

According to the further modification illustrated in Figure 7, the control mechanism comprises an upwardly extending shaft 70 fitted with a bevel wheel 7' which is in mesh with a bevel wheel h fixedly mounted upon or formed as one piece with, a nut sleeve 9, as in Figure 1. In Figure 7, however, the nut sleeve g is mounted as an extension of a stern bearing tube I9 supported by a stern bracket 20 and so that it is free to revolve but is prevented from moving axially. For this purpose, the rear end of the nut sleeve 9 is formed with a flange 2| which is engaged between the forward end of the bear- I ing tube I9 and a retaining ring 22 bolted to the bearing tube I9 suitable rings 23 being inserted in the parts I9 and 2| for taking the thrust and for sealing the space between the end of the bearing tube I9 and the flange 2 I. The nut sleeve g works on the screw threaded end portion of a long sleeve 24 which extends through the stern bearing tube I9 and has mounted on its outer end the flange l of the thrust coupling described with reference to Figure 1. The bore of the sleeve 24 is fitted with liners 25 to serve as bearing surfaces for the propeller shaft c, and the bore of the tube I9 is fitted with a liner 26 to serve as bearing surface for the long sleeve 24 which turns and slides during a pitch-changing operation. The control gearing ha'lc may be within the vessel if the flange part 21 is attached to the stern structure of the vessel.

I claim:

1. Pitch varying mechanism for marine propellers comprising in combination, blades pivotally'mounted on pintles so as to be turnable thereabout, toothed gears at the roots of the blades, axially movable and guided rack rods meshing with said gears, screw means operative for moving said rods axially, one element of said screw means having a flange with annular faces, a segment on each of said rack rods said segments comprising radial wall portions embracing said flange on both sides, and thrust pads rockably mounted on said radial wall portions of said segments and operatively contacting against respective annular faces of said flange.

2. Pitch varying mechanism for marine pr0 pellers as claimed in claim 1, wherein the thrust pads are of synthetic resin material and rockably mounted on respective radial wall portions by the aid of pivot pins projecting from said wall portions, the said pads being fitted each with a metal back plate arranged and fixed on an end portion of a respective pad and to one side of the pivot, thereof whereby each pad is free to tilt slightly out of its normal plane and about an edge of said back plate.

3. Pitch varying mechanism for marine propellers as claimed in claim 1, wherein the propeller boss is formed with a hub extension provided with guide means parallelwith the axis of the propeller shaft and each of said segments is formed with a projection slidable with guidance in said guide means.

ERNEST CHARLES HATCHER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,914,754 Munk June 20, 1933 2,019,965 Havill Nov. 5, 1935 2,172,932 Cairns Sept. 12, 1939 2,240,873 Thomas May 6, 1941 2,272,128 Osbourne Feb. 3, 1942 FOREIGN PATENTS Number Country Date 578,534 Great Britain July 2, 1946 688,367 France May 12, 1930 123,453 Austria June 25, 1931 

